This invention relates generally to pool cleaning systems of the type including a so-called automatic pool cleaning device adapted for travel over submerged surfaces of a swimming pool or the like to pick up and collect accumulated debris such as leaves, twigs, sand and silt. More particularly, this invention relates to a rotatable hose coupling for installation along a flexible hose used for connecting the pool cleaner to a hydraulic power source such as a suction or vacuum source by connection to the suction side of a conventional pool water filtration system. The rotatable hose coupling of the present invention is designed to incrementally rotate or index the flexible hose through a part-circle step each time the filtration system is cycled on and off.
Pool cleaner systems and related devices are generally well known in the art for use in maintaining residential and commercial swimming pools in a clean and attractive condition. In this regard, swimming pools conventionally include a water filtration system equipped with a pump for drawing or suctioning water from the pool for circulation through a filter canister having filter media therein to remove and collect water-entrained debris such as leaves and twigs as well as fine particulate including sand and silt. In a typical arrangement, at least a portion of the pool water is vacuum-drawn over a weir mounted within a so-called skimmer well positioned substantially at the water surface to draw and collect floating debris to the filter equipment. From the filter canister, the water is recirculated to the pool via one or more return lines. Such filtration equipment is normally operated for several hours on a daily basis and serves, in combination with traditional chemical treatments such as chlorination or the like, to maintain the pool water in a clean and clear sanitary state. However, the water filtration system is ineffective to filter out debris which settles onto submerged floor and side wall surfaces of the swimming pool. In the past, settled debris has typically been removed by coupling a vacuum hose to the suction side of the pool water filtration system, such as by connecting the vacuum hose to the skimmer well located near the water surface at one side of the pool, and then manually moving a vacuum head coupled to the hose over the submerged pool surfaces to vacuum settled debris directly to the filter canister where it is collected and separated from the pool water. However, manual vacuuming of a swimming pool is a labor intensive task and is thus not typically performed by the pool owner or pool cleaning service personnel on a daily basis.
So-called automatic pool cleaner devices have been developed over the years for cleaning submerged pool surfaces, thereby substantially eliminating the need for labor intensive manual vacuuming. Such automatic pool cleaners typically comprise a relatively compact cleaner housing or head coupled to the pool water filtration system by a hose and including water-powered means for causing the cleaner to travel about within a swimming pool to dislodge and collect settled debris. In one form, the pool cleaner is connected to the return or pressure side of the filtration system for receiving positive pressure water which powers a turbine for rotatably driving cleaner wheels, and also functions by venturi action to draw settled debris into a filter bag. See, for example, U.S. Pat. Nos. 3,882,574; 4,558,479; 4,589,986; and 4,734,954. In another form, the pool cleaner is coupled by a vacuum hose to the suction side of the filtration system, whereby water is drawn through the pool cleaner to operate a drive mechanism for transporting the cleaner within the pool while vacuuming settled debris to the filter canister of the pool filtration system. See, for example, U.S. Pat. Nos. 3,803,658; 4,023,227; 4,133,068; 4,208,752; 4,643,217; 4,679,867; 4,729,406; 4,761,848; 5,105,496; 5,265,297; 5,634,229; and 6,094,764.
For optimum cleaning efficiency, it is desirable for the pool cleaner to traverse submerged pool floor and side wall surfaces with sufficient and relatively constant traction to maintain vacuuming structures in close proximity with submerged pool surfaces. In addition, it is desirable for the pool cleaner to travel in a substantially random pattern to insure coverage of most or all submerged pool surfaces within a relatively short period of time. However, the traction and random travel characteristics of a given pool cleaner can be adversely affected by the flexible hose which can take a "set" in a particular deformed or curved configuration in response to aging and/or exposure to thermal cycling during normal use. When the flexible hose assumes a particular set shape, the hose can provide resistance to pool cleaner movement both in terms of traction and random travel. In some pools, assumption of a set hose shape can result in the pool cleaner traveling along a repeatable and thus non-random path whereby the pool cleaner may not cover and thus does not clean large portions of the pool. In addition, when this occurs, the same discrete surfaces of the hose can repeatedly scrub against abrasive plaster pool water surfaces to cause premature hose leakage and failure. Spiral wound or corrugated flexible hoses of the type normally used with suction powered pool cleaners are especially susceptible to assuming an undesirable set shape during use.
Swivel couplings have been designed for use with flexible hoses coupled to a pool cleaner, wherein the swivel couplings are typically installed at spaced-apart locations along the hose length to rotatably interconnect a plurality of hose segments. See, for example, U.S. Pat. Nos. 4,558,479; 5,195,563; and 5,775,741. During normal operation of the pool cleaner, the swivel couplings are intended to accommodate relative rotation between adjacent hose segments in the course of normal hose twisting and turning as the pool cleaner travels about within the pool. While such relative rotation between hose segments can be effective in minimizing or eliminating the hose "set" problem, such swivel couplings function passively to permit some hose rotation and do not function actively to insure at least some hose rotation on a regular basis. Moreover, prior swivel couplings have exhibited a tendency to bind and thus become nonfunctional upon intrusion of grit or silt present in the pool water. Accordingly, such prior swivel couplings have not resolved the hose "set" problem.
The present invention relates to a rotatable hose coupling designed for in-line connection along the flexible hose coupled between the pool filtration equipment and a pool cleaner. The rotatable hose coupling of the invention actively responds to pressure fluctuations associated with cyclic on-off operation of the filtration equipment to rotatably index the hose in a manner which prevents the hose from assuming a particular "set" shape.